Quantification of severity of mitral regurgitation by simple Doppler echocardiographic ''left ventricular early inflow-outflow index''

摘要

Background: Mitral regurgitation (MR) is the most commonvalvular pathology in practice. Characterization of the severity ofregurgitation is amongst the most difficult problems. Althoughechocardiography is the investigation of choice for detection ofMR, no gold standard exists for grading of severity. Guidelinesclassify MR according to parameters derived from color and spec-tral Doppler and anatomic measurements. A novel simple Dopplerderived parameter, left ventricular early inflow–outflow index(LVEIO), based onflowvelocity into the left ventricle (LV) in diastoleand ejected from the LV in systole was analyzed for quantificationof MR in correlation with currently recommended parameters.Methods: A prospective analytical study was performed intertiary care center in western India including consecutive 500patients diagnosed with MR on echocardiography from May 2015to July 2016. The examinations were performed using PhilipsIE33 Echocardiography machine (Koninklijke Philips, Netherlands).Assessment of MR was done according to recommendations forevaluation of the severity of valvular regurgitation by AmericanSociety of Echocardiography. Grading of severity was analyzedusing color flow jet, effective regurgitant orifice area (EROA) by theproximal isovelocity surface area (PISA) method, vena contractawidth (VC) and left atrial volume. Regurgitant volume and regurgitationfraction was calculated using Left Ventricular outflow tract(LVOT) diameter and LVOT Velocity time integral (LVOT VTI). Leftventricular early inflow outflow index (LVEIO) is a simplificationof the regurgitant volume method and uses only a single-pointmeasurement of early diastolic filling velocity (E) and LV outflowvelocity integrated over the systolic ejection period (LVOT VTI) andwas calculated by formula E/LVOT VTI.Results: LVEIO was 4.65±1.45, 6.56±1.52, 9.91±3.36 amongthose with mild, moderate and severe MR, respectively (P < 0.001).Linear increase in LVEIO was also noted across groups of increasingseverity of MR (P < 0.001). LVEIO was a significantly better discriminatorof severe MR compared with E-wave velocity alone(area under the curve 0.92 (95% CI 0.90–0.93) versus 0.84 (95%CI 0.81–0.86); P < 0.001. Those with LVEIO ≥8 were likely to havesevere MR (likelihood ratio 26.5), whereas those with LVEIO ≤4were unlikely to have severe MR (likelihood ratio 0.11). By multivariatelogistic regression analysis, LVEIO was independentlyassociated with severity of MR when compared with MR jet area,effective regurgitant orifice area (EROA), VC and regurgitant fraction(RF).Conclusion: Left ventricular early inflow outflow index (LVEIO)is a novel, simple Doppler echocardiographic parameter for estimationof severity of MR.